System for generating waves in a pool

ABSTRACT

Some embodiments are directed to a system for generating waves in a pool, including, in the region of at least one wall of the pool, at least one water intake mouth connected to a supply source by means of a network of pipes, the network of pipes including at least one pump capable of alternately transferring water from the supply source to the pool and vice versa, the pump being controlled so as to generate, in the region of the water intake mouth, an oscillating flow alternately oriented towards the pool and then towards the supply source.

CROSS REFERENCE TO RELATED APPLICATION(S)

This application is a national phase filing under 35 C.F.R. § 371 of and claims priority to PCT Patent Application No. PCT/EP2016/053695, filed on Feb. 22, 2016, which claims the priority benefit under 35 U.S.C. § 119 of European Patent Application No. 1551501, filed on Feb. 20, 2015, the contents of each of which are hereby incorporated in their entireties by reference.

BACKGROUND

Some embodiments relate to a system for generating waves in a pool. Some embodiments also relate to a system for recovering the energy of the waves.

Generating waves in a pool is usually done using oscillating mechanical devices, such as floats or beaters with vertical flaps. These devices oscillate vertically or horizontally by displacing a volume of water, which makes it possible to generate waves.

A generation of current is also possible using pumps that are usually placed on the edges or at the bottom of the pool. In this case, an operation in a closed loop is possible thanks to a recirculation pipe placed under the pool.

SUMMARY

Such systems for generating waves generally have problems linked to their mechanical complexity. This complexity is due in particular to the presence of many mobile parts, and, in the case of beaters with vertical flaps of the “dry-back” type, to the need to offset the hydrostatic thrust that is applied on the wet side of the beater.

Another problem with such systems for generating waves is that they require providing end stops that limit the maximum amplitudes of the movements. This limitation of the amplitude of the movement also limits the amplitude of the waves generated.

Another problem with such systems is that the combined generation of waves and of current requires implementing two types of devices: floats, for example, for the generating of waves and pumps for the generating of current. This is a source of additional complexity.

With regards to the recovery of the energy of the waves, also called wave energy, systems for recovering energy that implement turbines exist, however these systems are:

-   -   Either simple and inexpensive, but also not very effective such         as surge systems or oscillating water column systems;     -   Or that are high performance, but complex and expensive such as         oscillating systems with an active control.

This results in that in both cases the cost of the energy is too high with respect to the market.

Some embodiments address or resolve the related art systems for generating waves in a pool. Some embodiments are directed to a system for generating waves in a pool that is simple and effective, and which is not mechanically limited for the amplitude of the generated waves. Some embodiments are directed to a system for simultaneously generating waves and current that is simple and easy to implement.

Some embodiments are directed to a system for recovering energy from waves that is simple, inexpensive and high performing.

Some embodiments are directed to a system for generating waves in a pool, characterised in that it includes, in the region of at least one wall of the pool, at least one water intake mouth connected to a supply source by a network of pipes, the network of pipes including at least one pump which is capable of alternately transferring water from the supply source to the pool and vice versa, the pump being controlled so as to generate in the region of the water intake mouth an oscillating flow alternately oriented towards the pool then towards the supply source.

As such, the system according to some embodiments uses pumps for the generating of waves. The latter generate an oscillating flow that locally creates a vertical variation in the surface elevation of the water, this variation propagates and as such generates waves effectively.

In more technical terms, the oscillating flow creates a condition at the limits in the fluid that locally imitate the kinematics of the waves. The propagation of this condition at the limits as such generates waves.

In addition, the use of pumps makes it possible to overcome end stops that limit the maximum amplitudes of the movements. As such, the amplitude of the waves generated is also not limited by these stops.

The term oscillating flow means a flow of which the quantity of water per second oscillates between a minimum value and a maximum value.

The pump used in this system can be any type of pump capable of pumping the water from the reservoir to the pool and vice versa. It is possible, for example, to use any type of motor pump, in particular, a propeller pump.

According to some embodiments, the generated oscillating flow has a non-zero average. Imposing an oscillating flow at a non-zero average flow, makes it possible to generate a current in addition to waves. As such, the same device used to generate waves is also used to generate a current. In this way, it is possible to simultaneously generate waves and current without any need to add additional devices.

According to some embodiments, the system also includes a converging portion that has inclined walls, placed at the outlet of the water intake mouth. Such a converging portion makes it possible to diffuse the stream generated by the pump in order to prevent it from being concentrated in a reduced zone. This makes it possible to enhance or optimize the profile of the flow created in such a way as to better approach a conventional profile of a wave. As such, the performance of the device is further improved.

According to some embodiments, the water intake mouth is inclined by an angle alpha with respect to the bottom of the pool.

Advantageously, the outlet of the water intake mouth is provided with a structure in the shape of a honeycomb. Such a structure in the shape of a honeycomb makes it possible to break any swirling structures that would be generated by the pump.

According to some embodiments, the supplying of the pump with water is done from a reservoir located upstream from the water intake mouth. This reservoir is, for example in the open air.

Advantageously, the pool includes an end opposite the wall including the water intake mouth, and the reservoir, is connected to the opposite end by a second network of pipes. For example, these pipes pass under the bottom of the pool.

According to some embodiments, the reservoir in the open air consists of a second pool, which can be, for example, identical to the initial pool.

According to an alternative, the supplying of the pump with water is done directly in the pool, with the network of pipes connecting the water intake mouth to at least one opening at the bottom of the pool. Preferably the network of pipes connects the water intake mouth to several openings at the bottom of the pool. Such a supplying directly at the bottom of the pool has the advantage of not requiring any additional reservoir.

Advantageously, the opening or openings at the bottom of the pool are located at an end opposite that including the pipe for generating waves. This makes it possible to not disturb the generation of waves.

Advantageously, the opening at the bottom of the pool has a flared shape. Such a shape, also makes it possible to limit the disturbances in the generating of waves.

According to another embodiment, the water intake mouth is integrated into a structure that is maintained floating by sliding along a vertical guide column. The fact that the water intake mouth is integrated into a floating structure makes it possible to optimise the generation of waves. Indeed, in this case the oscillating flow is generated near the surface of the water tout while still avoiding the intake of air when the pump is operating as suction.

Advantageously, the pump is placed upstream from the water intake mouth on a support that is above the level of the water. This configuration makes it possible in particular to facilitate the access to the pump for maintenance.

According to an alternative, the system for generating waves includes several water intakes mouths placed one above the other.

Some embodiments are also directed to a system for recovering energy of sea waves, wherein it includes a sealed support structure including at least one water intake mouth connected to a network of pipes for removing water, the network of pipes for removing water including,

-   -   at least one pump controlled in such a way as to generate a loss         of load that is proportional to the acceleration of the flow of         water with the purpose of reducing the effects of inertia linked         to the mass of water contained in the network of pipes, and     -   at least one turbine actuated by the flow of water in order to         produce electrical energy.

As such, the system for recovering energy proposed by some embodiments is simple and inexpensive since it is based on the use of pumps for the generating of a flow and turbines for the production of electrical energy. In addition, controlling the flow makes it possible to reduce the apparent inertia of the system. Because of this, the output of the turbine during the energy recovery cycles is improved. As such, the global output of the system is also improved.

The term reduction in the apparent inertia means the fact that, without control, the system behaves as a mass-damper unit subjected to an excitation force. In order to enhance or maximize global output, the speed of the flow has to be in phase with the excitation force. Without control, the mass term is dominant. The speed of the flow is then out of phase by 90° with respect to the excitation force. The global output is low. With the controlling of the flow by the pump, the apparent mass is reduced in such a way that the damping term is dominant. The speed of the flow is then in phase with the excitation force and the global output is substantially improved.

The network for removing water is also used for the network for supplying the pump with water when the latter is in discharge mode.

The pump used in this system for recovering energy can also be any type of pump capable of pumping water from the reservoir to the pool and vice versa. It is possible, for example, to use any type of motor pump, in particular a propeller pump.

According to an alternative, the pump and the turbine are coupled. The term coupled means the fact that the pump and the turbine belong to the same device or form the same device. For example, the turbine can be replaced with the propellers of a propeller pump.

According to an application, the speed of the flow is measured by a sensor positioned in the network of pipes. Such a sensor is for example a flow meter.

According to some embodiments, the sealed support structure is a wall of a dike. As such, this system can be installed in a shallow amount of water on the wall of a dike, for example. In this way the protection of the coastline and the production of energy are mutualized.

According to another embodiment, the water intake mouth is mounted floating on a float maintained in position by anchoring lines. This structure allows the system to be installed at a great depth.

According to some embodiments, the removing of water is done directly in the sea, with a vertical pipe being submerged at a determined depth. In the case where the system is positioned at great depth, the pipe is submerged directly in the water at a determined depth considered to be sufficient. Such a depth must be at least equal to the half-wavelength of the dominant wave on site. Such a pipe can be maintained in position by a solid structure. On the other hand, in the case of a system positioned at a shallow depth, it is preferable that the pipe pass through the wall of the dike and open into the open sea.

The term dominant wave on site means the wave that is reproduced most often in a zone.

According to some embodiments, the outlet of the water intake mouth is provided with a converging portion with inclined walls. These inclined walls have the advantage of concentrating the flow of water at the inlet of this water intake mouth.

BRIEF DESCRIPTION OF THE FIGURES

Other characteristics and advantages shall appear more clearly when reading the following description, of particular embodiments, provided as non-limiting examples, in relation with the annexed drawings wherein:

FIG. 1 shows a system for generating waves in a pool according to some embodiments without which the supplying of the pump with water is done par a reservoir located upstream from the water intake mouth;

FIG. 2 shows an alternative of the system of FIG. 1 wherein the supplying of the pump with water is done directly in the pool;

FIG. 3 shows an alternative of the system of FIG. 2 wherein the water intake mouth is floating;

FIGS. 4 and 5 show two alternatives of a system for recovering energy from waves that can be used at a shallow depth;

FIG. 6 shows a system for recovering energy from waves that can be used at a great depth;

FIG. 7 shows a system for generating waves similar to the system of FIG. 1 wherein the water intake mouth is inclined by an angle α;

FIG. 8 shows a system of FIG. 7 wherein the pool further communicates with the reservoir by a pipe arranged in the bottom of the pool;

FIG. 9 shows a system of FIG. 8 wherein the water intake mouth further includes a honeycomb;

FIG. 10 shows a system similar to the system of FIG. 8 which includes two superposed water intake mouths;

FIG. 11 shows a system similar to the system of FIGS. 1 and 7 wherein the reservoir is a second pool.

DETAILED DESCRIPTION OF THE EMBODIMENTS

An example of a system for generating waves in a pool 1 is shown in FIG. 1. This system includes a water intake mouth 2 including a pipe 3 through which the pool 1 communicates with a reservoir 4. A pump 5 positioned in the pipe 3 is controlled in such a way as to generate a flow of water that has an oscillating flow alternately oriented towards the pool 1 then towards the reservoir 4. The flow at an oscillating flow created as such makes it possible to generate waves 6 in the pool 1.

In the example of FIG. 1, the water intake mouth 2 includes a converging portion that has inclined walls 7. This converging portion makes it possible to diffuse the flow generated by the pump in order to prevent it from being concentrated in a reduced zone. Diffusing the flow generated makes it possible to have waves with a better profile, i.e. that approach the profile of sea waves.

The water intake mouth 2 is also provided at its outlet with a structure in the shape of a honeycomb 7. This structure 8 makes it possible to break any swirling structures that would be generated by the pump.

The system for generating waves of FIG. 1 also makes it possible to generate a current without the need to add other devices. For this, an average non-zero flow is imposed at the oscillating flow generated at the outlet of the water intake mouth.

The term positive flow designates the flow generated by the pump when the latter is oriented in a particular direction, for example towards the pool. When the pump is oriented in the direction opposite to the particular direction, the flow is considered negative. The term non-zero flow designates the fact that the oscillating flow generated by the pump is oriented more in one direction than the other. As such, in order to generate a current in the pool, the pump is oriented more in the direction of the pool than in the opposite direction.

An alternative of the system for generating waves of FIG. 1 is shown by FIG. 7.

This system includes a pool 1000 including a wall 2000 that forms a water intake mouth and a pipe 3000 through which the pool 1000 communicates with a reservoir 4000. A pump 5000 positioned in the pipe 3000 is controlled in such a way as to generate a flow of water that has an oscillating flow alternately oriented towards the pool 1000 then towards the reservoir 4000, in order to generate waves 6000 in the pool 1000. This system includes with respect to the system of FIG. 1, the following particularities:

-   -   the bottom of the reservoir is lower than the bottom of the         pool. This has the interest of allowing for an inclination of         the pipe.     -   the pipe 3000 is inclined by an angle α with respect to the         bottom of the pool 7000. The interest of such an inclination is         to optimise the profile of the current generated in the pool in         the case of generation of a swell.     -   pool including a beach 8000 for damping waves, of which the         interest is to dampen the waves generated when they arrive at         the opposite end 2001 of the wall 2000 of the pool 1000.

The reservoir 4000 is for example a reservoir in the open air.

The angle α is for example between 0 and 15 degrees, preferably 5 degrees.

FIG. 8 shows an alternative of the embodiment of FIG. 7, wherein the pool 1000 has under the bottom 7000, a pipe or a network of pipes 9000 allowing for a communication between the bottom 7000 of the pool 1000 and the reservoir 4000. In FIG. 8, the pipe 9000 opens into the bottom 7000 of the pool 1000 in the region of an opening 1001 located in the region of the end 2001 opposite the wall 2000 that forms the water intake mouth.

The pipe 9000 has the advantage of allowing for the circulation of a current generated by the pump when a non-zero flow is imposed. The circulation of the current generated is done from the pool to the reservoir, as shown by the arrows.

FIG. 9 shows a system similar to the system of FIG. 8, but wherein the water intake mouth 2000 includes a structure 10000 in the shape of a honeycomb.

FIG. 10 shows a system similar to the system of FIG. 9, but wherein the water intake mouth 2000 includes the structure 10000 in the form of a honeycomb and two superposed pipes 3001, 3002 provided respectively 5001, 5002. According to an alternative this system does not include any honeycomb.

FIG. 11 shows a system similar to the system of FIGS. 1 and 7 wherein the reservoir is in the form of a second pool 4001.

This second pool 4001 can be identical to or different from the initial pool 1000.

The advantage of this embodiment is to make it possible to generate waves and/or current in the two pools. Furthermore, in this embodiment the pipe 3004 includes a pump 5003 and structures in the shape of a honeycomb 10001, 10002 respectively on the side of the initial pool 1000 and on the side of the second pool 4001. However, these structures in the shape of a honeycomb 10001, 10002 are optional.

In the same way, it is possible to have several pipes each provided with a pump and which are arranged next to one another and/or superposed.

It can also be provided that the pipe or pipes, be inclined towards one of the two pools 1000, 4001. Of course for all of the embodiments shown, it is possible to generate current in addition to generating waves.

A second embodiment of a system for generating waves according to some embodiments is shown in FIG. 2. This system is identical to the preceding system except in what relates to the supply source of the pump. Instead of having a reservoir, the supplying of the pump 15 is done directly in the pool 10. This supplying is done by a pipe 19 via an opening 11 that is at the bottom of the pool. In order to not disturb the generation of waves in the pool, it is particular that this opening be as far as possible from the water intake mouth 12. It is also particular that this opening have a flared shape. This opening 11 can also be replaced with several petites openings at the bottom of the pool 10 connected to the pipe 19.

FIG. 3 shows an alternative of the embodiment of FIG. 2. In this case the water intake mouth 22 is mounted floating by sliding along a vertical guide column 31. This arrangement makes it possible to generate an oscillating flow close to the surface of the water. This arrangement also makes it possible to prevent taking in air when the pump is operating as suction since the water intake mouth 22 follows the drop and the rise of the water level of the wave, i.e. the passing from a crest to a trough. In order to further improve the system for generating waves, the pump 25 is mounted upstream from the water intake mouth on a support 32 that is located above the level of the water. The pump 25 is connected to the water intake mouth 22 by a flexible pipe 30. The other elements of this system for generating waves are unchanged with respect to the system of FIG. 2. The operation of the pump also remains identical to the two preceding examples.

An example of a system for recovering energy from waves 100 at sea is shown in FIG. 4. This system includes a water intake mouth 101 including a pipe 102 to be connected to a reservoir 103. This pipe 102 includes a pump/turbine pair 104 controlled in such a way as to effectively generate electrical energy from the kinetic energy of the waves. The water intake mouth is positioned in a sealed structure 105, for example the wall of a dike. A converging portion 106 that has inclined walls is positioned on this sealed structure 105 at the inlet of the water intake mouth in such a way as to converge the flow of water towards the inlet of this water intake mouth, which has for effect to accelerate the flow.

In order to enhance or optimize the output of the turbine, the pump is controlled in such a way as to produce a loss of load that is proportional to the acceleration in order to reduce the apparent inertia of the water contained in the network of pipes. To do this, a sensor 107 positioned in the pipe measures the speed of the flow continuously.

FIG. 5 shows a second embodiment of a system for recovering energy from waves according to some embodiments. This system is identical to the system of FIG. 4, except with regards to the removing of water and the supplying of the pump. Instead of having a reservoir, the removing of water when the pump is sucking and the supplying of the pump when it is in discharge mode, these are done by a pipe 108 via an opening 109 in the sealed structure 105. It is particular that this opening 109 be as deep as possible in order to prevent disturbing the measurements of the sensor 107. It is also particular to have this pipe open farther out at sea, i.e., as far as possible from the sensor.

FIG. 6 shows a system for recovering energy from waves according to some embodiments that can be used at a great depth. In this system, the water intake mouth 200 is mounted on a float 201 maintained in position by the anchoring lines 202.

The water intake mouth 200 is connected to a pipe 203 submerged in the water at a sufficient depth, for example 50 m below the level of the water. The latter is terminated by an opening in the shape of a converging portion 204. A solid structure 205, integral with the structure 201, is used to maintain the pipe 203. In the same way as for the embodiments described in reference to the FIGS. 4 and 5, the pump/turbine pair 206 cooperates with a sensor 207 positioned upstream from the water intake mouth 200. The controlling of this system also remains identical to the systems of FIGS. 4 and 5.

Optionally this system also includes a converging portion positioned at the inlet of the water intake mouth in order to concentrate the flow of water at the inlet of this water intake mouth 200. 

1. A system for generating waves in a pool having at least one wen, the system, comprising: at least one water intake mouth, in a region of the at least one wall of the pool; a supply source by a network of pipes connected to the last one water intake mouth, the network of pipes including at least one pump which is capable of alternately transferring water from the supply source to the pool and vice versa, the pump being controlled so as to generate in the region of the water intake mouth an oscillating flow which is alternately oriented towards the pool then towards the supply source; and an open-air reservoir the supplying of the pump with water is performed using the open-air reservoir located upstream from the water intake mouth.
 2. The system for generating waves according to claim 1, wherein the oscillating flow has a non-zero average.
 3. The system according to 2, further comprising a converging portion that has inclined walls, placed at the outlet of the water intake mouth.
 4. The system for generating waves according to claim 1, wherein the water intake mouth is inclined by an angle alpha with respect to the bottom of the pool.
 5. The system for generating waves according to claim 1, wherein the outlet of the water intake mouth is provided with a structure in the shape of a honeycomb.
 6. The system for generating waves according to claim 1, wherein the pool includes an end opposite the wall including the water intake mouth, and in that the open-air reservoir is connected to the opposite end by a second network of pipes.
 7. The system for generating waves according to claim 1, wherein the open-air reservoir consists of a second pool.
 8. The system for generating waves according to claim 1, further comprising several water intake mouths placed on top of one another.
 9. The system according to claim 2, further comprising a converging portion that has inclined walls, placed at the outlet of the water intake mouth.
 10. The system for generating waves according to claim 2, wherein the water intake mouth is inclined by an angle alpha with respect to the bottom of the pool.
 11. The system for generating waves according to claim 3, wherein the water intake mouth is inclined by an angle alpha with respect to the bottom of the pool.
 12. The system for generating waves according to claim 2, wherein the outlet of the water intake mouth is provided with a structure in the shape of a honeycomb.
 13. The system for generating waves according to claim 3, wherein the outlet of the water intake mouth is provided with a structure in the shape of a honeycomb.
 14. The system for generating waves according to claim 4, wherein the outlet of the water intake mouth is provided with a structure in the shape of a honeycomb.
 15. The system for generating waves according to claim 2, wherein the pool includes an end opposite the wall including the water intake mouth, and in that the open-air reservoir is connected to the opposite end by a second network of pipes.
 16. The system for generating waves according to claim 3, wherein the pool includes an end opposite the wall including the water intake mouth, and in that the open-air reservoir is connected to the opposite end by a second network of pipes.
 17. The system for generating waves according to claim 4, wherein the pool includes an end opposite the wall including the water intake mouth, and in that the open-air reservoir is connected to the opposite end by a second network of pipes.
 18. The system for generating waves according to claim 5, wherein the pool includes an end opposite the wall including the water intake mouth, and in that the open-air reservoir is connected to the opposite end by a second network of pipes.
 19. The system for generating waves according to claim 2, wherein the open-air reservoir consists of a second pool.
 20. The system for generating waves according to claim 3, wherein the open-air reservoir consists of a second pool. 